Conventionally, a valuable sheet substance such as a paper sheet or a photograph is usually covered with a protective film for protection because such an article is readily suffered from damage. Typically, a sheet laminating apparatus is used for laminating a sheet substance between two pieces of plastic films.
Generally, the conventional sheet laminating apparatus lacks a thickness detecting mechanism. That is, the laminating operation is done under a predetermined parameter. For example, the temperature and/or the rotating speed of the heating roller are adjusted to a proper level. In a case that the sheet substance is too thick or too thin, the laminating operation is readily suffered from failure. Take a sheet substance having a thickness exceeding the allowable specification for example. If the temperature of the heating roller is insufficient or the rotating speed of the heating roller is too fast, the plastic films are not completely softened and thus the sheet substance fails to bond with the plastic films to form a laminated structure.
Therefore, there is a need of providing a sheet laminating apparatus having a thickness-detecting function for detecting the thickness of the article to be laminated so as to dynamically adjust the temperature and/or the rotating speed of the heating roller of the sheet laminating apparatus.